Homeless youth are widely acknowledged as being a particularly medically vulnerable population in the US. Homeless youth are at high risk for negative outcomes from various environmental stressors, individual coping mechanisms, and poor access to appropriate primary health care. The multidimensional health problems of homeless youth are known. Factors related to monitoring and improving quality of primary health care for this population are not well documented. I propose to conduct research to document the factors necessary for monitoring access and quality of primary health care for homeless youth. The present study of monitoring the quality of health care for homeless youth will be a mixed-method study. It begins with a qualitative component, consisting of narrative interviews with street-based and service-based homeless youth to document their understandings of illness, health care, and experiences with seeking health care. It then includes focus groups with homeless youth to record their perspectives about appropriate process and outcome measures of quality of health care. This is complemented by national expert consensus on appropriate process and outcome measures of quality health care using a modified Delphi technique. Finally, the research will include a pilot testing study of existing youth health-related quality of life instruments that are deemed appropriate to this population based on results of the previous research components. The resulting data will assist in local and national health care monitoring and planning for this vulnerable population. This research will position me to plan and conduct a larger evaluation study of the quality of health care and of public policies impacting health for homeless youth. In addition, this career development award will allow me the didactic and experiential training necessary to transition to an independent clinical investigator focusing on health services research for homeless and high-risk adolescents.